Anti-hammer apparatus for powered imprinters

ABSTRACT

Anti-hammer apparatus which provides only a selected interval in which the print drums of a powered imprinter may be locked in a fixed relationship is provided in accordance with the teachings of the present invention. Upon a failure to achieve locking within such selected interval, a locking circuit is disabled to prevent repeated attempts at locking from damaging the print drums and/or the locking mechanism therefor.

United States Patent St. Jean [451 Nov. 7, 1972 [54] ANTI-HAMMER APPARATUS FOR POWERED IMPRINTERS [72] Inventor: Lloyd E. St. Jean, Huntington, N.Y.

[73] Assignee: Interface Industries, Inc., Hauppauge, NY.

221 Filed: Aug. 19,1971

21 Appl. No; 173,144

[52] US. Cl ..101/99 [51] Int. Cl. ..B4lj 7/34 [58] Field of Search ..101/99, 110, 93 C, 93 R, 93

[56] References Cited UNITED STATES PATENTS 2,910,935 11/1959 Gignetti ..10l/93C 3,100,440 8/1963 Wales ..101/93 C 3,176,610 4/1965 Benson et al ..101/93 C 3,179,044 4/1965 Schierbeek ..101/93 C 3,636,871 l/l972 Speicher ..101/95 3,664,259 5/1972 Weinkle ..101/99 Primary Examiner-William B. Penn Attorney--Louis E. Mam et al.

[5 7 ABSTRACT Anti-hammer apparatus which provides only a selected interval in which the print drums of a powered imprinter may be locked in a fixed relationship is provided in accordance with the teachings of the present invention. Upon a failure to achieve locking within such selected interval, a locking circuit is disabled to prevent repeated attempts at locking from damaging the print drums and/or the locking mechanism therefor.

10 Claims, 3 Drawing Figures PATENTEDnuv 1972 1 4 AIL Prlnf Drums ANTI-HAMMER APPARATUS FOR POWERED IMPRINTERS This invention relates to anti-hammer apparatus for powered imprinters and more particularly to apparat us which provides only a selected interval in which the print drums of a powered imprinter may be locked in a fixed relationship and upon a failure to achieve locking within such selected interval, the locking circuit is disa bled to prevent repeated attempts at locking from damaging the print drums and/or the locking mechanism therefor.

ln powered imprinters employed to print sales and credit card information or the like on a credit card sales form or similar other forms it is usually desirableto lock properly set print drums in a fixed position so that when the print roller is energized, the information set on such print drums will be clearly printed on the sales form without distortion associated with a shifting of the print drums when the force of the moving roller is imposed thereon. This desirable technique of locking up the properly set print drums becomes a virtual necessity in powered imprinters relied upon in remotely located sales terminals within an integrated, prior approval type, credit sales systems as a fraud preventing device to ensure that only a sale for the amount approved is consummated. For instance, in integrated credit card sales systems of the type wherein remotely located sales terminals are directly or selectively linked to a central computer which maintains account information and/or acts to continuously update account information as sales information is received from the remotely located sales terminals, it is usual for the clerk or other sales person located at the remote sales terminal to obtain prior approval from the central station before consummating the credit sale. Although this may be done by a telephone call to a supervisor monitoring the account, it is automatically accomplished in more advanced integrated credit card sales systems to avoid the undue consumption of time necessitated by a manual check. In at least one such advanced system, once the remote sales terminal is energized, a data link to the central computer or station is established and the information obtained from the credit card presented together with the setting of the print drums of the powered imprinter with the amount of the sale and such other information as is required by the system results in a transmission of the appropriate data to the central computer or station so the status of the account may be checked to determine whether or not the sale in question should be approved. If the sale is to be approved, the powered imprinter at the inquiring sales terminal may be energized by the remotely located central computer or station to thereby cause the credit card sales slip to be automatically imprinted by the action of a moving roller or the like in such manner that an authorization of the sale by the central computer or station results in the immediate consummation thereof. However, to safeguard such system from fraud, it is necessary to lock the properly set print drums in a fixed position immediately prior to or during the data transmission to the central computer or station so that the sale approved is the sale consummated and thereby preclude a condition wherein one amount may be transmitted to the central computer or station for approval while the setting of the print drums are thereafter altered to allow an approval obtained under one set of conditions to effect a sale for a larger amount.

Powered imprinters employed to print sales and credit card information or the like on a credit card sales form or similar other forms in such advanced system often take the form of a flat base plate member having an identification plate thereon which sets forth the location of the powered imprinter and any other appropriate information, which is fixed in character, associated with the sales location to be credited with the sale. The flat base plate member additionally has a portion thereof devoted to receiving a credit card and an apertured section through which raised characters on a plurality of print drums protrude; The print drums are set by levers, slide switches or any other convenient setting means for the amount of the sale and any other information which may be desired and the area of the flat base plate occupied by the identification plate, the credit card and the apertured section through which the raised characters on the plurality of print drums protrude is such that a credit card sales form or similar other forms may be placed in an overlying relationship therewith so that the portions thereof adapted to receive location, credit-card and sale information are in appropriate registration with the raised indicia therefor on the flat base plate. Thus, when a roller bar or other appropriate pressure imposing member is rolled over the surface of a credit card sales form in place'on the flat base plate, location, credit-card and sales information will be imprinted thereon in the wellknown manner.

The plurality of print drums employed in such powered imprinter devices take the form of a plurality of drums each of which has a plurality of raised characters spaced about the cylindrical periphery thereof. In addition each drum has a locking aperture associated with each character-thereon disposed intermediate adjacent raised characters. The plurality of locking apertures may occupy peripheral areas of the print drum which are similar in area to that occupied by each character thereon and it will be appreciated by those of ordinary skill in the art that in each case, the locking aperture associated with a particular character on a print drum will be disposed on the cylindrical surface of the print drum at a location which is substantially removed from its associated character so that when this character is set to protrude through the flat base plate of the powered imprinter, the locking aperture therefor may be readily engaged from the underside of the flat base plate. The plurality of print drums are mounted along a common axis and gear means, also arranged along such common axis and disposed intermediate each print drum, are provided for each print drum so the same may be set to print a desired character by slide switches or lever arms having means to engage said gear means.

After each of the print drums have been set so that a plurality of desired characters protrude through the aperture in the flat base plate, the credit card and the credit card sales forms are appropriately positioned on the fiat base plate of the powered imprinter and steps are taken to cause a roller bar or other appropriate pressure imposing member to traverse across the flat base plate and thereby imprint the credit card sales form in the well-known manner. Prior to the actual enabling of the roller vbar and in the case of an. advanced form of integrated credit sales system where automatic presale authorization is required, as aforesaid, prior to or during the automatic transmission required for presale authorization, thelocking apertures ,associated with the protruding character on each print drum are engaged so that the plurality of preset print drums are locked ina fixed relationship until the sale is consummated. As all of .the protruding characters should be aligned, the locking apertures therefor should also be aligned. Thus, the means for engaging the plurality of locking apertures may take the form of a plurality of locking fingers appropriately spaced along a relay actuated locking bar which is appropriately positioned so .thatupon the actuation of said relay the bar is shifted into a position wherein each-of the locking fingers engages. the aligned print drum locking aperture associated therewith to prevent further rota tion of all of therprint drums until the relay is de-energized subsequent to the completion of the sale.

While in theory the foregoing technique for locking up the plurality of preset print drums should function well, it often occurs that one of the plurality'of print drums is carelessly preset so that the protruding character selected thereon is not properly aligned with the remaining protruding characters and hence the locking .aperture associated therewith is not properly aligned with the locking apertures to be engaged on the remaining ones of the plurality of print drums. Under the conditions imposed in powered imprinter apparatus, not only will one nonaligned locking aperture prevent all of the locking fingers on the relay actuated locking bar from engaging their associated locking apertures in the plurality of preset print drums, but in addition thereto serious damage can result to the powered imprinter apparatus therefrom. This can be appreciated by a realization that under the nonaligned conditions mentioned above, when the relay. of' the relay actuated locking bar is energized, the locking finger associated with the nonaligned aperture will strike the surface of the improperly set print drum rather than engaging the appropriate locking aperture thereof. When the locking finger strikes the surfaceof the improperly set print drum in response to the energization of the relay actuated locking bar the remaining locking fingers will be prevented from engaging the aligned locking apertures in their associated print drums and the impact of the locking finger onthe surface of the nonaligned print drum will cause the locking finger and hence the bar on which it is mounted to bounce back. However, as the relay of the relay actuated locking bar remains energized, the locking bar is again urged toward an engaging position whereby the locking finger associated with the improperly set print drum again strikes the cylindrical surface thereof. This sets up a condition between the surface of the nonaligned print drum and the locking finger associated therewith which resemblesthe reciprocatingi mpacting action of a pneumatic drill or electric hammer and can result in serious damage to the impacting locking finger, the surface of the nonaligned drum and/or an impacted, raised character thereon if not the actual destruction thereof. Thus it will be appreciated that under conditions wherein one of the plurality of preset print drums is improperly aligned, the locking mechanism for such plurality of print drums can effectively beat the system to pieces ONe possible solution to the foregoing problem is to provide detent means for the slide switchesor lever means which serve to set the positions of the print drums so that the characters selected thereon may only be set in the appropriate aligned protruding position. However, as each print drum would normally be provided with at least 10 raised alphanumeric characters or the like and the slide switches or lever means used to set the desired positions of the print drums would rarely have an operational displacement range which exceeds 2 or 3 inches; this solution would invariably result in slide switches that were s o stiff that they would be difficult to operate and hence detract from the simple and easy operation of the'ad'vanced integrated credit sales system as a whole. 1

Therefore it is a principal object of this invention to provide anti-hammer apparatus for a plurality .of print drums which acts under normal conditions to lock each of said plurality of print drums in a fixed relationship but is responsive to a condition where locking is not achieved in a selected interval to prevent repeated attempts at locking from damaging the plurality of print drums and/or the locking apparatus therefor. Various other objects and advantages-of the present invention will become clear from the following detailed description of several exemplary embodiments thereof, and the novel features will be particularly pointed out in conjunction with the appended claims.

a In accordance with the present invention, antihammer apparatus for actuating locking bar means having a plurality of locking fingers thereon for engaging aligned locking apertures in a plurality of print drums is provided for placing said locking bar means in an engaging position with respect to the aligned apertures in said plurality of locking fingers; said apparatus including switch means being adapted for closure when said locking bar means is in a fullyengaged condition and circuit means for selectively enabling and disabling said actuating whenever said circuit means is placed in first and second states, respectively; said circuit means being placed in a first state in response to an actuating input signal applied thereto and being placed in a second state whenever said switch means remains in an open condition after the expiration of .a predetermined interval whereby said actuating means is automatically disabled whenever said locking bar means fails to properly engage.-

The invention will be more clearly understood by reference to the following detailed description of several exemplary embodiments thereof in conjunction with the accompanying drawings in which:

FIG. 1 illustrates exemplary print drum and associated locking bar structure typical of the type employed with the apparatus according to the present invention;

FIG. 2 is a block diagram schematically illustrating one embodiment of the anti-hammer apparatus according to the instant invention; and

FIG. 3 is a block diagram schematically illustrating another embodiment of the anti-hammer apparatus according to the present invention.

drums l-6 concentrically mounted about the axisA- A. Each of said print drums 1-6 has a plurality of raised alphanumeric characters 0-9 disposed about the periphery of the cylindrical surface thereof; however, as will be apparent to those of ordinary skill in the art any desired information could be present thereon in raised form and of course, any number of print drums could be selected depending on the nature and amount.

of infonnation to be imprinted. Intermediate each of the raised characters 0-9 on each of the print drums 1-6 is a locking aperture L which, although'here shown as having a rectangular shape, may take any convenient form which may be readily fabricated. Each of the locking apertures L occupies approximately the same area on the cylindrical periphery of each of the print drums 1-6 as does a'raised character 0-9, although wide variations are arbitrarily available to suit design preferences. Each of the plurality of locking apertures L on each of the print drums L6 is associated with one of the raised characters 0-9 thereon and it will be ap preciated by those of ordinary skill in the art that as each of the raised characters 0-9 is designed to protrude through an aperture in a flat base plate member (not shown), as aforesaid, when in a particular position, i.e., here the top position for example, the locking aperture L associated with a particular character 0-9 on a print drum 1-6 will be disposed on the cylindrical surface of the print drum l-6 at a location which is substantially removed from its associated character 0-9 so that when this character is set to protrude through the flat base plate (not shown), the locking aperture therefor may be readily engaged from the underside of the flat base plate by the locking bar.

structure illustrated. Thus, for example, the locking aperture L associated with a particular raised character 0-9 may be removed therefrom about the periphery of the print drums l-6 by an angular displacement of 180 degrees or another convenient displacement accommodating engagement from the underside of the flat base plate (not shown) may be employed. The plurality of print drums l-6 are mounted for rotation on a shaft 7 and gear means (not shown), also mounted for rotation about shaft 7 and fixedly mounted to each of the print drums 1-6, are disposed intermediate adjacent ones of said plurality of print drums 1-6 so that each of the plurality of print drums 1-6 may be set to print a desired character in the well-known manner by slide switches or lever means (not shown) having means to engage said gear means.

The locking bar structure shown in FIG. 1 takes the form of an elongated member 8 having a plurality of locking fingers 16' disposed thereon in a manner to be appropriately spaced with respect to each of the pluthat of the locking apertures L; however, when the locking apertures L are rectangular as shown in FIG. 1, the locking fingers may either take the rectangular form illustrated or a pyramidal form which may facilitate locking under conditions of minor misalignment. Additionally, the locking fingers l -6 should exhibit sufficient structural rigidity so that once engaged within the locking apertures L, the print drums 1-6 may not be further rotated about shaft 7 and the crosssectional dimensions of the locking fingers 1'-6' should be sufficiently close to the aperture size of the locking apertures 1.. so that when the locking fingers 1'-6' are fully engaged, very little play is available for the further rotation of the print drums l-6. The elongated member 8 is rigidly connected through a linkage 9 to a relay 10 in such manner that when the relay 10 is energized, in a manner more fully described below in conjunction with FIGS. 2 and 3, the elongated member 8 is vertically displaced toward the plurality of printdrums l-6 so as to engage the lockingapertures therein associated with the raised characters selected. The relay 10 may be entirely conventional, accepting either an a.c. or d.c. supply voltage, and when energized will displace the elongated member 8 in a vertical direction so that the locking fingers 16' thereon will engage the locking apertures in the plurality of print drums l-6 opposite thereto, assuming such locking apertures are properly aligned. A switch means 12, which may take the form of a microswitch orother suitable switch means,.is appropriately positioned so that the armature 13 thereof is engaged by the elongated member 8 in such manner that the switch means 12 is placed in its closed condition by the full depression of plunger contact 14 only when the elongated member has been vertically displaced a sufficient distance so that the locking fingers 1'6"nearly seat in the associated aligned locking aper- @251 of the plurality of print drums 1-6. As will be apparent, should the raised characters which have been set on the print drums 1-6 not be properly aligned due to an inaccurate setting, the locking apertures L therefor will not be properly aligned and the locking fingers 1-6' will not seat. Under such nonaligned condition, the armature 13 will not fully depress the plunger contact 14 and thus the switch means 12 will remain in an open condition. Accordingly it will be seen that whenever the relay 10 is actuated and the locking fingers l'6 seat in their associated locking apertures L, the switch means 12 will be placed in a closed condition; however, should a nonaligned condition of the appropriate locking apertures L prevent the locking fingers l'-6 from seating, switch means 12 remains in an open condition. The function of the switch means 12 as well as the condition thereof within the anti-hammer apparatus according to the present invention will be rendered manifest in connection with rality of print drums l-6 so that said locking fingers 1'-6' will engage the properly aligned locking apertures L in each of said print drums 1-6 when the elongated member is displaced in a direction toward the plurality of print drums 1-6. The locking fingers 1'-6' will normally exhibit the same shape cross-section as the description of FIGS. 2 and 3.

FIG. 2 is a block diagram schematically illustrating one embodiment of the anti-hammer apparatus according to the instant invention. The exemplary embodiment of the anti-hammer apparatus illustrated in FIG. 2 comprises first and second relay means 10 and 16, semiconductive switch means 17 and timing circuit means 18. The first relay means 10, as indicated by the reference numeral thereof, corresponds to the relay means 10 shown in FIG. 1 and is employed, as

7 aforesaid, to vertically displace the elongated locking bar 8. Additionally in FIG. 2, the locking bar 8, and the plurality of print drums 1-6 have been indicated by the appropriately annotated blocks shown and it will be appreciated that the relative motion of the locking bar 8 under. conditions wherein the first relay means 10 is energized is indicated by dashed arrows A and B. The solenoid winding 19 of the first relay means 10 is connected through switch contact 21 at terminals 20-20 to a supply source (not shown) which may here be considered to be a conventionalac. supply. The second relay 16.may be'a-conventional d.c. relay suitable for closing the single switch contact 21 coupled thereto when the same is energized. The solenoid winding 22 of the second relay means 16 isconnected in series with the semiconductive switch means 17 and the timing circuit 18. The semiconductive switch means .17 may take the form of a conventional NPN transistor as shown or other well-known .forms of semiconductive switch means capable of being placed in an on condition by a pulse applied to the control electrode thereof may be employed or alternatively manual or relay actuated switch means may be relied upon. In the case of the NPN transistor shown in FIG. 2, thecollector is connected to the solenoid winding 22 of the second relay means 16, while the emitter, electrode is connected to ground as shown. The semiconductive switch means 17 is placed in a conductive condition by a pulse input, as indicated, applied to the control electrode thereof which here corresponds to the base of the NPN transistor shown. As will be understood by those of ordinary skill in the art, a positive level input will be applied to the base of the semiconductiveswitch means 17 whenever the print drums 16 are to be locked in place, i.e., prior to or during ajr'eq uest to a central station for presale authorization or any other time desired prior to printing, and such positive level input will be maintained on the base of semiconductive switch means' 17 until such time as it is desirable to disengage the locking fingers 16 which normally would occur atthe completion .of a transaction or sale. The timing circuit 18 comprises a parallel R-C network connected intermediate the positive d.c. supply B+ and the solenoid winding 22 of the second relay means 16. The timing circuit 18 includes three parallel branches .wherein the first branch includes a large value resistor R the second branch includes a relatively large capacitor C,.' while the third branch includes the switch contacts of the switch means 12, described in conjunction with FIG. 1 and the relatively low value resistor R Exemplary values for the components in the timing circuit 18 are such that R, may be selected at 2,0009, C may be selected at l50p.f and R, may be selected at 100'.

In the operation of the exemplary embodiment of the anti-hammer apparatus shown in FIG. 2, whenever the print drums 1-6 are to be locked in the fixed position to whichthey were set, i.e., at a time subsequent to the setting of the print drums 1-6 and/or prior to or during a request to a central station for presale authorization or at any other time desired prior to printing, a positive input level as indicated in FIG. 2 is applied to the control electrode of the semiconductive switch means 17 which here takes the form of the base of the NPN transistor shown. The positive level applied to the base of the semiconductive switch 17, as well known to the solenoid winding 22 of the second relay means 16 .and the collector-emitter path'of the NPN transistor shown for the semiconductive switch 17. When current flows through the solenoid winding 22 of the second relay means 16, the second relay means 16 will be energized to close switch contact 21 which thereby completes the circuit for the solenoid winding 19 of the first relay means '10 connected to an ac. supply (not shown) through terminals 20-20". The closure of switch contact 21 thereby energizes the first relay means 10 whereby the locking bar 8 is displaced in the vertical direction to enable the locking fingers l6 thereon to engage aligned locking apertures L' on the plurality of print drums 1-6 in the manner described above in connection with FIG. 1. If the selected raised characters were properly set in an aligned condition the locking apertures L-therefor in the plurality of print drums 1-6 will be properly aligned and may be easily engaged by the locking fingers 1 6"=on the locking bar 8 upon the energization of thefirst. relay means 10. Under theseconditions, the switch means 12 will be placed in a closed condition due to the engagement between the armature 13 thereof and the locking bar 8 when the locking fingers l'-6 are nearly seated as aforesaid to thereby complete the third branch of, the timing circuit '18. However, if thelocking apertures L in the print drums 1-6 are not aligned, the locking fingers 1-6' will not seat so that the locking bar 8 fails to place switch means 12 in a closed condition whereby the third branch of the timing circuit l8 remains open circuited. This latter condition, if allowed to, continue in the absence of the present invention, could result in damage to the system due to the reciprocating hammer effect which is established between the print drum in which the nonaligned aperture resides and the impacting locking fingers 1"6', asaforesaid.

When 7 the semiconductive switch 17 is initially placed in a conducting condition by the positive level applied to the base thereof as aforesaid, switch means 12 in the third branch of timing circuit 18.will be in an open condition and current flow to ground from the 13+ supply through the serially connected solenoid winding 22 of the second d.c. relay 16 and the collector-emitter path of the semiconductive switch means 17 will occur essentially through capacitor C due to the large impedance of the resistor R in the first branch of the timing circuit 18. However, as is well known to those of ordinary skill in the art, as the capacitor C begins to charge, the current flow therethrough will be reduced and will be essentially cut off when the capacitor C is fully charged. The time constant associated with the charging of the capacitor C is determined by the capacitance exhibited thereby'and the resistance exhibited by the current path to ground. This time constant should be such that the capacitor C is fully charged within an interval corresponding to a time after the locking fingers should have seated such as 20 ms. When the capacitor C is fully charged, current flow therethrough will be essentially zero. Therefore, as current flow through resistor R is too small to retain the second relay means 16 in an energized condition, this resistor being only provided to establish a long time-constant discharge path for capacitor C during intervals when the semiconductor switch means 17 is deenergized; the second relay means 16 will be deenergized to disengage switch contact 21 unless an alternate current path for the solenoid winding 22 of the second relay means 16 has by this time been established through the third branch of timing circuit 18 due to the closure of the switch means 12. Therefore, as switch contacts 21 effectively controls the connection of the solenoid winding 19 of the second relay to its supply voltage connected to terminals and 20' and the switch means 12 is only closed by the action of the locking bar 8 when the locking fingers 1'-6 are nearly seated; it will be appreciated that the relay 10 which displaces the locking bar 8 in a direction to engage the locking fingers l-6 thereon with appropriately alignedlocking apertures L in the plurality of print drums 1-6 will be deenergized unless the locking fingers l -6' seat in the appropriate locking apertures L therefor within thetime limit established by the charging time constant of capacitor C and hence that imposed by the timing circuit 18. Thus, conditions wherein a locking fingers on the locking bar 8 is continuously impacting the surface of an improperly set print drum can not here obtain, because improper alignment of the locking apertures L for the selected raised characters on print drums 1-6 prevent the switch means 12 from beingplaced in a closed condition as this will only occur upon the seating of the locking fingers 1'-6' and hence the first relay means 10, which functions to urge the locking bar 8 into engagement, will be deenergized at the completion of the charging of capacitor C upon a failure of the locking fingers 1'-6' to seat in properly aligned locking apertures L in the print drums 1-6. Therefore, the instant invention ensures that if the locking fingers 1'6' do not properly engage within a predetermined interval, the locking bar 8 is disengaged so that a condition wherein an impacting locking finger acts like a reciprocating hammer is avoided together with the resulting damage which attends such condition.

FIG. 3 illustrates another exemplary embodiment of the anti-hammer apparatus according to the present invention. The embodiment of the invention illustrated in FIG. 3 may employ many of the same components illustrated in FIG. 2 and described above. Therefore, in the embodiment of the invention illustrated in FIG. 3, components which are common to those illustrated in FIG. 2 have been provided with the same reference designations used therein and it shall be understood that such commonly designated components as are shown in FIG. 3 may take the same form and perform the same function as their counterparts which were described in conjunction with FIG. 2.

The exemplary embodiment of the anti-hammer apparatus according to the present invention, as shown in FIGS. 3, comprises first and second relay means 10 and 16, semiconductive switch means 17 and an input timing and control circuit 30. The first relay means 10, as indicated by the reference numeral, takes the same form of relay described in conjunction with FIG. 2 and is connected and performs the same precise function as the first relay means 10 discussed in conjunction with FIG. 2. Thus, the solenoid winding 19 of the first relay means 10, as shown in FIG. 3; is connected through switch contact 21 to an ac. supply (not shown) applied to terminals 20-20. Similarly, the operation of the first relay means 10 is precisely that described in conjunction with FIG. 2 in that, as indicated in FIG. 3, it acts when energized to displace the locking bar 8 toward an engaging relationship with the locking apertures L of the plurality of print drums 1-6 so that switch means 12 is placed in a closed condition when the locking fingers 16 seat while such switch means 12 remains in an open condition should such locking fingers l -6' fail to properly seat. The second relay means 16 and the semiconductive switch means 17, as indicated by their respective reference numerals, take the same form and perform the same function as their counterparts described in FIG. 2. Thus, the emitter of the NPN transistor shown as the semiconductive switch means 17 is connected to ground while the collector thereof is connected to-the solenoid winding 22 of the second relay means 16. The other terminal of the solenoid winding 22 is, however, connected directly to the B+ supply indicated so that the solenoid winding 22 and the collector-emitter path of the NPN transistor shown as the semiconductive switch means 17 are-connected in series directly between ground and the positive supply B+. The semiconductive switch means 17, as will be apparent to those of ordinary skill inthe art, is again placed in an on or conducting condition by a positive level applied to the control electrode thereof which here constitutes the base and when the semiconductive switch means 17 is rendered conductive in this manner it will be appreciated that the second relay means 16 will be energized to thereby close switch contact 21 and thus energize the first relay means 10 which displaces the locking bar 8 into an engaging relationship with the appropriate Iocking apertures in the plurality of print drums 1-6.

The input timing and control circuit 30 comprises flip-flop 32, AND gate 34, timing means 36 and the OR gate 38. The flip-flop 32 may take the form of a conventional bistable multivibrator or other conventional binary circuit means which acts in the well-known manner to provide a positive level at the output thereof connected to conductor 40 in response to a pulse input applied at input terminal 42 and maintains such positive level until it is reset, whereupon a ground or low level output is applied to conductor 40. The input terminal 42 serves as the input terminal to the exemplary embodiment of the anti-hammer apparatus depicted in FIG. 3 and it will be understood that a pulse is applied thereto each time it is desired to lock up the properly preset plurality of print drums l-6. The output of the flip-flop 32 is connected through conductor 40 to one input of AND gate 34 and through conductor 44 to an input of timing means 36. The timing means 36 may take the form of a conventional one-shot device such as a monostable multivibrator or schmitt trigger. Thus the timing means 36responds to each input pulse received thereby when it is in its stable state by switching to its unstable state to produce an output pulse whose duration is equal to the duty cycle thereof or the time in which the timing'circuit 36 remains in its unstable state. The duty cycle of the timing circuit 36 may typically be in the range of 5-500 ms depending on the mechanical resonance of the system and/or the driving frequency, and the output of the timing circuit 36 is applied through conductor 46 to one input of the OR gate 38.

output level whenever both inputs thereto are positive,

while providing a low or ground output level whenever one or more of the inputs thereto are low orat ground level. One input to AND gate 34 is'connected through conductor 40 to the output of flip-flop 32, as aforesaid, while a second input thereto is connected through switch means 12 to the positive supply B+. The output of AND gate 34is connected through conductor 48 to another input to OR gate 38. The OR gate 38 may be entirely conventional, taking any of the well-known forms of this common type of logic means. Accordingly, OR gate 34 acts in the conventional manner to provide a positive output whenever one or more of the inputs-thereto are positive while providing a low level. or ground output level when both of the inputs thereto are low or at ground. The output of the OR gate 38 is connected through conductor 50-to the control electrode-or base of the semiconductive switch means 17. I. I 1

' In the operation of the exemplary embodiment of the anti-hammer apparatus according to this invention as shown in FIG..3, whenever theprint drums 1 6 are to be locked in the fixed position to which they were set, i.e., at a time subsequent tofthe settingof the print drums 1-6 and/or prior to or during a request to central station for presale authorization or at any other time desired prior to printing, a positive input level or pulse will be applied tothe input terminal 42 which serves as the input to flip-flop 32. This input to flip-flop 32 will cause this bistable device to toggle to its positive state to thereby provide a positive level to one input of AND gate 34 through conductor 40 and to the input of timing means 36. Under the initial conditions here posed, the locking bar 8 isdisengaged, the switch means 12 will be in an open condition and hence the input conditions applied to AND gate 48 are such that it remains in a low or' ground level output state. The positive level applied to the input of timing means 36 through conductor 44 will, however, drive this device into its unstable state whereby a pulse is produced thereby on con- I ductor 46 and will have a duration, as aforesaid, in the range of approximately -500 ms. The output of the timing means 36 is applied to one input of the OR gate 38 and will cause the OR gate to produce a positive level at the output thereof even though the other input thereto from AND gate 34 is low. The positive level output of the OR gate 38 is applied to the base of semiconductive switch means 17 through conductor 50 and serves in the well-known manner to drive the semiconductive switch means 17 into its conductive state. When the semiconductive switch means 17is thus driven into conduction, current flowing from the B+ supply to ground through the solenoid winding 22 of the second relay means 16 and the collector-emitter path of the semiconductive switch device 17, will energize the second relay means 16 which thereby closes switch contact 211 to in turn energize the first relay means 10. The first relay means 10, when energized,

acts in themanner described above to displace the locking bar 8 in a direction so that the locking fingers 16' thereon will tend to engage the appropriate locking apertures L on the plurality of print drums 1-6, it being recalled that if such locking apertures are properly aligned, the locking fingers l'-6' will seat therein to effect the closure of switch means 12 while if proper seating does not occur switch means 12 remains in an open condition. Thus it is seen that when an input signal isinitially applied to the input terminal 42 of the flip-flop 32, the toggling of flip-flop 32 and the fixed duration pulse produced in response thereto by the timing means 30 will cause the semiconductive switch means 17 to be initially placed in the on condition to thereby energize the firstand second relay-means l0 and 16 causing the locking bar 8 to tend to engage.

If t it is assumed that the locking apertures L are properly aligned, the locking fingers l-6 on locking bar 8 will be properly seated therein and hence the switch means 12 will be placed in a closed condition thereby applying the B+ supplylevel to the second inputof AND gate 34. As the first input to AND gate 34 already has the positive level at the output of flipflop 32 applied thereto, when the second input thereof receives the B+ supply level, the input conditions on AND gate34 will be appropriate for the production of a high or positive level output. This'positive level output is applied through conductor 48 to the second input of OR gate. 38 to maintain the input conditions thereon appropriate for the production of a positive output on conductor 50. Thus, when switchmeans 12 is closed, the OR gate 38 will maintain a positive level on the base of semiconductive switch means 17 to maintain. such switch means 17. in an on condition even when the output of the timing means 36 terminates. Accordingly,

when the locking fingers 1' 6 are properly seated and switch means 12 is closed, the semiconductive switch means 17 and hence the first relay means 10 remains on to thereby maintain the locking bar 8 in an engaged position until such'time as the imprinting operation is completed and flip-flop 32 is reset. However, should a nonaligned condition occur, the switch means 12 will remain in on open condition so that AND gate 48 remains in a low or ground level output state. When this occurs the output of OR gate 38 will go low at the termination of the fixed duration pulse from the timing means 36 to thereby place the semiconductive switch means 17 in an off condition which thereby deenergizes the first and second relay means 10 and 16. Accordingly, it will be seen that if the locking fingers 16 on locking bar 8 do not properly seat within the fixed time interval established by the duty cycle of timing circuit 36,- the first relay means ,10 is deenergized so that damage to the nonaligned print drum. and impacting locking finger is avoided. Thus, this exemplary embodiment of the instant invention also ensures that if the locking fingers 1'--6'v do not properly engage within a predetermined interval, the locking bar 8 is disengaged so that a reciprocating hammer condition capable of doing substantial damage to the impacting locking fingers and print drums is avoided.

Although the present invention has been disclosed in conjunction with several rather specific exemplary embodiments thereof, many modifications and alternatives to the exemplary embodiments of the antihammer apparatus disclosed herein will be apparent to those of ordinary skill in the art. Thus, alternate logic configurations and input states could be substituted for those described above and any well-known form of timing configuration could be substituted for those shown 13 without any deviation from the inventive concepts disclosed herein.

While the invention has been described in connection with several exemplary embodiments thereof, it will be understood that many modifications will be readily apparent to those of ordinary skill in the art; and this application is intended to cover any adaptations or variations thereof. Therefore, it is manifestly intended that this invention be only limited by the claims and the equivalents thereof.

What is claimed is: l

1. In imprinting apparatus including a plurality of print drums and means for locking said plurality of print drums in a set imprinting relationship, each of said plurality of print drums having a plurality of characters thereon arranged to be selectively disposed in a set imprinting relationship and having engageable lock means thereon for being selectively engaged by said means for locking said plurality of print drums in a set imprinting relationship, wherein the improvement comprises:

firstmeans when energized in response to an input signal for displacing said means for locking said plurality of print drums toward an engagingrelationship with said engageable lock means on each of said plurality of print drums;

second means responsive to a proper engagement between said means for locking and said engageable lock means for maintaining said first means in an energized condition; and

third means responsive to a failure of said locking means to properly engage said engageable lock means within a predetermined interval for deenergizing said first means.

2. The improved apparatus according to claim 1 wherein said first means comprises relay means for displacing said means for locking said plurality of print drums toward an engaging relationship with said engageable lock means on each of said plurality of print drums and semiconductive switching means for energizing said relay means in response to an input signal.

I 3. The improved apparatus according to claim 2 wherein:

said third means comprises timed circuit means for maintaining said semiconductive switching means in a conductive condition for only a predetermined interval subsequent to the receipt of said input signal; and

said second means comprises switch means responsive to a proper engagement between said means for locking and said engageable lock means for maintaining said semiconductive switching means in a conductive condition subsequent to the termination of said predetermined interval.

4. The improved apparatus according to claim 3 wherein said engageable lock means on said plurality of print drums comprises locking apertures therein and said means for locking said plurality of print drums in a set printing relationship comprises locking bar means having a plurality of spaced locking fingers thereon for engaging said locking apertures, said switch means being positioned with respect to said locking bar means in such manner that it is closed thereby when said spaced locking fingers are nearly seated in said locking apertures.

5. The improved apparatus according to claim 4 wherein said semiconductive switching means comprises transistor means having first, second and third electrodes and responsive to the application of an input applied to saidfirst electrode to establish current flow between said second and third electrodes, said relay means being energized to displace said locking bar means toward an engaging relationship with said locking apertures in response to current flow between said second and third electrodes of said transistor means.

6. The improved apparatus according to claim 5 wherein said timed circuit means is connected in series with said second and third electrodes and said switch means is connected in parallel with said timed circuit means, said timed circuit means allowing. current to flow therethrough for only said predetermined interval whereupon said relay means is deenergized upon the termination, of said predetermined interval unless said' switch means has been closed by the proper. engagement of said locking bar means. i I

7. The improved apparatus according to claim 6 wherein said timed circuit means includes capacitor means which charges in response to the passage of current therethrough.

8. The improved apparatus according to claim 5 wherein said first electrode of said transistor means may receive an input applied thereto through said timed circuit means and said switch means, said timed circuit means being responsive to said input signal to apply an input to said first electrode for only said predetermined interval whereupon said relay means is deenergized upon the termination of said predetermined interval unless said switch means has been closed by the proper engagement of said locking bar means. I

9. The improved apparatus according to claim 8 wherein said timed circuit means comprises monostable multivibrator means which produces an output signal of said predetermined duration in response to said input signal, said output signal of said predetermined duration being applied an an input to said first electrode of said transistor means.

10. The improved apparatus according to claim 9 additionally comprising:

OR gate means adapted to receive first and second input signals and produce an output signal in response thereto, said output signal of said OR gate means being applied as an input to said first electrode of said transistor means, said OR gate means having one input thereto connected to said monostable multivibrator means;

AND gate means adapted to receive first and second input signals and produce an output only in response to the receipt of both said first and second input signals, an output of said AND gate means being connected to another input of said OR gate means, one input of said AND gate means being connected to said switch means and being adapted to receive an input signal therethrough; and

flip-flop means being adapted to produce an output in response to the application of said input signal thereto, an output of said flip-flop means being connected to another input of said AND gate tivibrator means. 

1. In imprinting apparatus including a plurality of print drums and means for locking said plurality of print drums in a set imprinting relationship, each of said plurality of print drums having a plurality of characters thereon arranged to be selectively disposed in a set imprinting relationship and having engageable lock means thereon for being selectively engaged by said meAns for locking said plurality of print drums in a set imprinting relationship, wherein the improvement comprises: first means when energized in response to an input signal for displacing said means for locking said plurality of print drums toward an engaging relationship with said engageable lock means on each of said plurality of print drums; second means responsive to a proper engagement between said means for locking and said engageable lock means for maintaining said first means in an energized condition; and third means responsive to a failure of said locking means to properly engage said engageable lock means within a predetermined interval for deenergizing said first means.
 2. The improved apparatus according to claim 1 wherein said first means comprises relay means for displacing said means for locking said plurality of print drums toward an engaging relationship with said engageable lock means on each of said plurality of print drums and semiconductive switching means for energizing said relay means in response to an input signal.
 3. The improved apparatus according to claim 2 wherein: said third means comprises timed circuit means for maintaining said semiconductive switching means in a conductive condition for only a predetermined interval subsequent to the receipt of said input signal; and said second means comprises switch means responsive to a proper engagement between said means for locking and said engageable lock means for maintaining said semiconductive switching means in a conductive condition subsequent to the termination of said predetermined interval.
 4. The improved apparatus according to claim 3 wherein said engageable lock means on said plurality of print drums comprises locking apertures therein and said means for locking said plurality of print drums in a set printing relationship comprises locking bar means having a plurality of spaced locking fingers thereon for engaging said locking apertures, said switch means being positioned with respect to said locking bar means in such manner that it is closed thereby when said spaced locking fingers are nearly seated in said locking apertures.
 5. The improved apparatus according to claim 4 wherein said semiconductive switching means comprises transistor means having first, second and third electrodes and responsive to the application of an input applied to said first electrode to establish current flow between said second and third electrodes, said relay means being energized to displace said locking bar means toward an engaging relationship with said locking apertures in response to current flow between said second and third electrodes of said transistor means.
 6. The improved apparatus according to claim 5 wherein said timed circuit means is connected in series with said second and third electrodes and said switch means is connected in parallel with said timed circuit means, said timed circuit means allowing current to flow therethrough for only said predetermined interval whereupon said relay means is deenergized upon the termination of said predetermined interval unless said switch means has been closed by the proper engagement of said locking bar means.
 7. The improved apparatus according to claim 6 wherein said timed circuit means includes capacitor means which charges in response to the passage of current therethrough.
 8. The improved apparatus according to claim 5 wherein said first electrode of said transistor means may receive an input applied thereto through said timed circuit means and said switch means, said timed circuit means being responsive to said input signal to apply an input to said first electrode for only said predetermined interval whereupon said relay means is deenergized upon the termination of said predetermined interval unless said switch means has been closed by the proper engagement of said locking bar means.
 9. The improved apparatus according to claim 8 wherein said timed circuit means comprises monostable multivibrator means which Produces an output signal of said predetermined duration in response to said input signal, said output signal of said predetermined duration being applied an an input to said first electrode of said transistor means.
 10. The improved apparatus according to claim 9 additionally comprising: OR gate means adapted to receive first and second input signals and produce an output signal in response thereto, said output signal of said OR gate means being applied as an input to said first electrode of said transistor means, said OR gate means having one input thereto connected to said monostable multivibrator means; AND gate means adapted to receive first and second input signals and produce an output only in response to the receipt of both said first and second input signals, an output of said AND gate means being connected to another input of said OR gate means, one input of said AND gate means being connected to said switch means and being adapted to receive an input signal therethrough; and flip-flop means being adapted to produce an output in response to the application of said input signal thereto, an output of said flip-flop means being connected to another input of said AND gate means and to an input of said monostable multivibrator means. 